<i>Herschel</i>/PACS observations of young sources in Taurus: the far-infrared counterpart of optical jets

Podio, L.; Kamp, I.; Flower, D. R.; Howard, Christian D.; Sandell, G.; Mora, A.; Aresu, G.; Brittain, S.; Dent, W. R. F.; Pinte, C.; White, G. J.

doi:10.1051/0004-6361/201219475

Cited by 54 publications

(123 citation statements)

References 76 publications

(132 reference statements)

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“…Podio et al (2012) showed that for four of these sources (T Tau, DG Tau A, FS Tau and RW Aur) the oxygen emission at 63 µm is spatially extended. They compared shock and disk model predictions for the fluxes of the [O ] 63 µm line, and found that these are likely dominated by jet/outflow emission.…”

Section: Oxygen Line Fluxesmentioning

confidence: 99%

[O I] disk emission in the Taurus star-forming region

Aresu

Kamp²,

Meijerink

et al. 2014

A&A

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Context. The structure of protoplanetary disks is thought to be linked to the temperature and chemistry of their dust and gas. Whether the disk is flat or flaring depends on the amount of radiation that it absorbs at a given radius and on the efficiency with which this is converted into thermal energy. The understanding of these heating and cooling processes is crucial for providing a reliable disk structure for interpreting dust continuum emission and gas line fluxes. Especially in the upper layers of the disk, where gas and dust are thermally decoupled, the infrared line emission is strictly related to the gas heating/cooling processes. Aims. We aim to study the thermal properties of the disk in the oxygen line emission region and to investigate the relative importance of X-ray (1-120 Å) and far-UV radiation (FUV, 912-2070 Å) for the heating balance there. This contrasts with what is predicted from our models. Possible explanations are that the disks in Taurus are less flaring than the hydrostatic models predict and/or that other disk structure aspects that were left unchanged in our models are important. Disk models should include flat geometries, varying parameters such as outer radius, dust settling, and the dust-to-gas mass ratio, which might play an equally important role for the [O ] emission. To improve statistics and draw more robust conclusions on the thermal processes that dominate the atmosphere of protoplanetary disks surrounding T Tauri stars, more L FUV and L X measurements are needed. High spatial and spectra resolution data is required to disentangle the fraction of [O ] flux emitted by the disk in outflow sources.

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Section: Oxygen Line Fluxesmentioning

confidence: 99%

[O I] disk emission in the Taurus star-forming region

Aresu

Kamp²,

Meijerink

et al. 2014

A&A

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“…15. Our calculations for Class 0 and I sources are supplemented by results from Podio et al (2012) for the Class II sources (average cooling of DG Tau A and RW Aur) that drive prominent jets. Similar to the selected line flux trends, a factor of 10 decrease in the CO and H 2 O cooling is detected for the Class I sources as compared to the Class 0 objects.…”

Section: Evolution From Class 0 To Class Imentioning

confidence: 99%

Water in star-forming regions withHerschel(WISH)

Karska

Herczeg

Dishoeck

et al. 2013

A&A

127

279

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Context. Understanding the physical phenomena involved in the earlierst stages of protostellar evolution requires knowledge of the heating and cooling processes that occur in the surroundings of a young stellar object. Spatially resolved information from its constituent gas and dust provides the necessary constraints to distinguish between different theories of accretion energy dissipation into the envelope. Aims. Our aims are to quantify the far-infrared line emission from low-mass protostars and the contribution of different atomic and molecular species to the gas cooling budget, to determine the spatial extent of the emission, and to investigate the underlying excitation conditions. Analysis of the line cooling will help us characterize the evolution of the relevant physical processes as the protostar ages. Methods. Far-infrared Herschel-PACS spectra of 18 low-mass protostars of various luminosities and evolutionary stages are studied in the context of the WISH key program. For most targets, the spectra include many wavelength intervals selected to cover specific CO, H 2 O, OH, and atomic lines. For four targets the spectra span the entire 55-200 μm region. The PACS field-of-view covers ∼47 with the resolution of 9.4 . Results. Most of the protostars in our sample show strong atomic and molecular far-infrared emission. Water is detected in 17 out of 18 objects (except TMC1A), including 5 Class I sources. The high-excitation H 2 O 8 18 -7 07 63.3 μm line (E u /k B = 1071 K) is detected in 7 sources. CO transitions from J = 14−13 up to J = 49−48 are found and show two distinct temperature components on Boltzmann diagrams with rotational temperatures of ∼350 K and ∼700 K. H 2 O has typical excitation temperatures of ∼150 K. Emission from both Class 0 and I sources is usually spatially extended along the outflow direction but with a pattern that depends on the species and the transition. In the extended sources, emission is stronger off source and extended on ≥10 000 AU scales; in the compact sample, more than half of the flux originates within 1000 AU of the protostar. The Conclusions. The PACS data probe at least two physical components. The H 2 O and CO emission very likely arises in non-dissociative (irradiated) shocks along the outflow walls with a range of pre-shock densities. Some OH is also associated with this component, most likely resulting from H 2 O photodissociation. UV-heated gas contributes only a minor fraction to the CO emission observed by PACS, based on the strong correlation between the shock-dominated CO 24-23 line and the CO 14-13 line. [O i] and some of the OH emission probe dissociative shocks in the inner envelope. The total far-infrared cooling is dominated by H 2 O and CO, with the fraction contributed by [O i] increasing for Class I sources. Consistent with previous studies, the ratio of total far-infrared line emission over bolometric luminosity decreases with the evolutionary state.

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“…An overview of the detected atomic and molecular species is shown in The HD J = 1−0 line at 112 μm has been detected toward TW Hya with a flux of 6.3 (±0.7) × 10 −18 W m −2 after deep integration (Bergin et al 2013 Podio et al (2012). Table 3 refers to the on-source position only (spectrum extracted from the central spaxel and corrected for PSF-loss, see Appendix D).…”

Section: Overviewmentioning

confidence: 99%

“…In this case, a further contribution to the OH lines may come from a shock associated with the molecular outflow/jet associated with the system. Indeed, compact warm OH emission has been observed to be associated with outflows in embedded young stellar objects (van Kempen et al 2010;Wampfler et al 2010Wampfler et al , 2013Podio et al 2012;Karska et al 2013). Further analysis including the mid-infrared lines (from Spitzer) is needed to disentangle the disk/outflow origin of OH for these systems.…”

Section: Origin Of Far-ir Emission Linesmentioning

confidence: 99%

DIGIT survey of far-infrared lines from protoplanetary disks

Fedele

Bruderer

Dishoeck

et al. 2013

A&A

114

146

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We present far-infrared (50−200 μm) spectroscopic observations of young pre-main-sequence stars taken with Herschel/PACS as part of the DIGIT key project. The sample includes 16 Herbig AeBe and 4 T Tauri sources observed in SED mode covering the entire spectral range. An additional 6 Herbig AeBe and 4 T Tauri systems have been observed in SED mode with a limited spectral coverage. Multiple atomic fine structure and molecular lines are detected at the source position:The most common feature is the [O i] 63 μm line detected in almost all of the sources, followed by OH. In contrast with CO, OH is detected toward both Herbig AeBe groups (flared and non-flared sources). An isothermal LTE slab model fit to the OH lines indicates column densities of 10 13 < N OH < 10 16 cm −2 , emitting radii 15 < r < 100 AU and excitation temperatures 100 < T ex < 400 K. We used the non-LTE code RADEX to verify the LTE assumption. High gas densities (n ≥ 10 10 cm −3 ) are needed to reproduce the observations. The OH emission thus comes from a warm layer in the disk at intermediate stellar distances. Warm H 2 O emission is detected through multiple lines toward the T Tauri systems AS 205, DG Tau, S CrA and RNO 90 and three Herbig AeBe systems HD 104237, HD 142527, HD 163296 (through line stacking). Overall, Herbig AeBe sources have higher OH/H 2 O abundance ratios across the disk than do T Tauri disks, from near-to far-infrared wavelengths. Far-infrared CH + emission is detected toward HD 100546 and HD 97048. The slab model suggests moderate excitation (T ex ∼ 100 K) and compact (r ∼ 60 AU) emission in the case of HD 100546.Off-source [O i] emission is detected toward DG Tau, whose origin is likely the outflow associated with this source. The [C ii] emission is spatially extended in all sources where the line is detected. This suggests that not all [C ii] emission is associated with the disk and that there is a substantial contribution from diffuse material around the young stars. The flux ratios of the atomic fine structure linesare analyzed with PDR models and require high gas density (n 10 5 cm −3 ) and high UV fluxes (G o ∼ 10 3 −10 7 ), consistent with a disk origin for the oxygen lines for most of the sources.

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Herschel/PACS observations of young sources in Taurus: the far-infrared counterpart of optical jets

Cited by 54 publications

References 76 publications

[O I] disk emission in the Taurus star-forming region

[O I] disk emission in the Taurus star-forming region

Water in star-forming regions withHerschel(WISH)

DIGIT survey of far-infrared lines from protoplanetary disks

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